This invention relates to the method and apparatus for indicating roller wear in a media handling device. Such structures of this type, generally, employ the use of a laser beam that is located adjacent to the media handling device roller. Initially, the roller material obstructs the laser beam. However, when the roller becomes worn out, the roller material no longer obstructs the laser beam and the beam shines on a piece of reflective material that is illuminated when the laser beam contacts it. This illumination will then be seen from the front of the media handling device, such as through the use of an LED. The laser beam can also activate an optical sensor that relays information to the user.
Prior to the present invention, as set forth in general terms above and more specifically below, it is known, in the media handling device art, to make use of a device for determining roller wear. Exemplary of such prior art is U.S. Pat. No. 6,055,047 (""047) to A. Schweizer et al., entitled xe2x80x9cDevice for Determining the Degree of Wear of a Paper Transport Roller.xe2x80x9d The ""047 reference discloses a paper transport roller which comprises two layers having different degrees of reflection for electromagnetic radiation. When the outer layer is worn, the degree of reflection of the surface of the paper transport roller changes and the user is signaled that paper transport roller must be replaced. However, if a foreign object becomes attached to the transport roller of the ""047 reference, this foreign object could adversely affect the reflection characteristics of the device. Also, if the paper transport roller does not wear evenly, one edge of the roller may have a different degree of reflection than the other edge of the roller and, possibly, adversely affect the reflection characteristics of the device. Therefore, a more advantageous paper transport roller wear indication system, then, would be presented if the system did not have to rely on a paper transport roller which comprises two layers having different degrees of reflection.
It is apparent from the above that there exists a need in the art for a paper transport roller wear indication system which is lightweight through simplicity of parts and uniqueness of structure, and which these equals the wear indication characteristics of the known paper transport roller wear indication systems, but which at the same time employs a laser beam which will alert the user to the worn condition of the paper transport roller. It is a purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.
Generally speaking, this invention fulfills these needs by providing a method for indicating media transport roller wear, wherein the method is comprised of steps of: impinging a coherent light beam upon a side of a media transport roller; and indicating when the media transport roller has worn down to a predetermined amount by causing the coherent light beam to pass over the media transport roller and interacting with a media transport roller wear indicating means.
In certain preferred embodiments, the coherent light beam is a laser beam. Also, the media transport roller wear indicating means includes a piece of reflective material and an LED located on the front of the media handling device which includes the media transport roller. Finally, the method further includes step of tracking the rotations of the media transport roller such that the coherent light beam would not need to be turned on until the media transport roller had completed a predetermined number of rotations.
In another further preferred embodiment, the wear of the media transport roller can be accurately detected so that the user can be alerted that the roller needs to be replaced and/or serviced.
In still another further preferred embodiment, an optical sensor can be utilized to sense the coherent light beam when the media transport roller has worn out. The optical sensor can then send this information to the media transport roller wear indicating means or over the network where the user is alerted of the state of the media transport roller.
The preferred media transport roller wear indicating system, according to this invention, offers the following advantages: lightness in weight; ease of assembly and repair; excellent roller wear indicating characteristics; good stability; good durability; and excellent economy. In fact, in many of the preferred embodiments, these factors of lightness in weight, ease of assembly and repair, excellent roller wear indicating characteristics, and excellent economy are optimized to an extent that is considerably higher than heretofore achieved in prior, known media transport roller wear indicating systems.
The above and other features of the present invention, which will become more apparent as the description proceeds, are best understood by considering the following detailed description in conjunction with the accompanying drawings, wherein like characters represent like parts throughout the several views and in which: